Attack Course Finder - Implementation

XLjedi · 01-09-09, 01:06 PM

I've been giving some thought this week about how to implement an Attack Course Finder in MoBo.

What I want to be able to do is take a picture of a ship on the horizon and with that, add a tool in MoBo that measures the observed length of the ship and then calculates the AoB. So for this we only need 2 bits of information the length of the ship and a measurement of the observed length (what we see thru our scope).

We'll assume for the moment that you are close enough to make a positive identification and with that, you can look up the exact length of the ship. Later, I suspect we'll be able to just put in approximations for different classes of ships and the calculation will still be valid to with a few degrees AoB. But for now, let's just assume we have perfect information about ship length.

Given the following...

So the ship is out there, I don't know how far away it is, but that's not important for determining AoB. All I do is get a measurement of the length of the ship as it appears in my scope. In this case I determine the length that I see is 34m.

I know the length of the ship (side c) is 95m. I just observed side a as 34m. Given these two measurements, I should be able to solve for angle bc which is equivalent to AoB. The formula in Excel would look like this:

Note: Excel trig functions return radians hence the 180/Pi conversion to degrees
=ASIN(34/95) * 180/3.14159265358979
=20.97°

So, I'm thinking that all I need is a gadget in MoBo that helps me measure the observed length of the ship, and if I know from the ship recog manual what the length is, I should be able to input those two values and get the AoB.

:hmm: Do you think this would work? ...not quite sure yet how to deal with the scaling issue of an observation; even at 1x mag. If a vertical stadimeter works wouldn't a horizontal one work as well? If anyone knows for sure that it's a lost cause trying to calculate "side a" just let me know.

XLjedi · 01-09-09, 03:16 PM

Hmmm... the more I think about it, the more I think it will be impossible to determine a true length for "side a" without knowing the distance.

Ah well, back to the drawing board.

Hitman · 01-10-09, 06:09 AM

Yes, I was about to point that out: You need the distance to the ship in order to be able of determining the AOB. Or at least, you need to calculate the "Aspect Ratio" as suggested in my tutorial for manual shooting with SH4: http://files.filefront.com/Simplifie.../fileinfo.html

Robert Fulton · 01-21-09, 02:58 AM

Maybe there is another method that could work in some if not all cases.

The horizontal measurements on the target vary with both distance and AOB. But vertical measurements vary only with distance. Can we not then use the ratio of the vertical measurements to the horizontal measurements compared to the known ratios from the ID manual to help us compute AOB?

(It is pushing 3:00am, so working on the actual formulas right now is not an option.)

XLjedi · 01-21-09, 09:48 AM

Quote:

Originally Posted by Robert Fulton

Maybe there is another method that could work in some if not all cases.

The horizontal measurements on the target vary with both distance and AOB. But vertical measurements vary only with distance. Can we not then use the ratio of the vertical measurements to the horizontal measurements compared to the known ratios from the ID manual to help us compute AOB?

(It is pushing 3:00am, so working on the actual formulas right now is not an option.)

The in-game stadimeter is designed to do that. It lets you take a vertical measurement to estimate distance. With the distance input the AoB math that I describe here would work.

I'm not necessarily against building a stadimeter tool in MoBo since it is intended to be a standalone app that might be applied in a situation where a stadimeter is not available.

I have a more pressing need in the MoBo tools department before going down the stadimeter path though. In the next update I want to add an "Angle" unit.

Robert Fulton · 01-21-09, 11:24 AM

Hmmm..... It seems it was later than I thought. Not only did I maybe misunderstand your original question, but I as I read Hitman's post, his reference to "aspect ratio" seems to cover the ground I did anyhow. (I have not downloaded his file, as I have yet to crack open SH4.)

Aaron, as I have stated previously, MoBo is awesome and I am appreciative of the effort and skill applied to create it. Also, congrats on your promotion to Ace of the Deep.

XLjedi · 01-21-09, 01:16 PM

Quote:

Originally Posted by Robert Fulton

Aaron, as I have stated previously, MoBo is awesome and I am appreciative of the effort and skill applied to create it. Also, congrats on your promotion to Ace of the Deep.

Thanks, glad you like it. ...are you using the 1.0 or latest Beta version?

Robert Fulton · 01-21-09, 02:18 PM

Quote:

Originally Posted by aaronblood

Thanks, glad you like it. ...are you using the 1.0 or latest Beta version?

Currently I am in Florida far from my desktop PC and MoBo. I downloaded the beta, but did not get time with it before leaving home. I do have an old laptop here, and may be able to load the beta and play around with it a little. I am also working on getting SH3 to run on a Mac here; if that works out I'll have SH3 and will definitely get the beta up and going.

I like your ideas for further development of MoBo, including user mods, more use of color, etc. I am still woefully a novice at SH3, but the modding/documenting/posting community is getting me up to speed. Your own posts, and those of Lurker, have been very helpful.

Hitman · 01-21-09, 04:39 PM

As much as MoBo was developed initially for SH3/4, IMHO it should shine even more when used in modern sub warfare games like Sub Command or Dangerous Waters

There you do bearings-only TMA with different legs and need more calculations and geometry than with WW2 tactics.

XLjedi · 01-21-09, 05:46 PM

Quote:

Originally Posted by Hitman

As much as MoBo was developed initially for SH3/4, IMHO it should shine even more when used in modern sub warfare games like Sub Command or Dangerous Waters

There you do bearings-only TMA with different legs and need more calculations and geometry than with WW2 tactics.

Some day I'm actually gonna have to play Dangerous Waters. I bought it (and the huge spiral-bound manual) and I've never bothered to play it beyond a few of the basic frigate missions.

01-09-09, 01:06 PM	#1
XLjedi Ace of the Deep Join Date: Jun 2005 Location: Palm Beach, Florida Posts: 1,243 Downloads: 53 Uploads: 8	Visual Attack Course Finder? I've been giving some thought this week about how to implement an Attack Course Finder in MoBo. What I want to be able to do is take a picture of a ship on the horizon and with that, add a tool in MoBo that measures the observed length of the ship and then calculates the AoB. So for this we only need 2 bits of information the length of the ship and a measurement of the observed length (what we see thru our scope). We'll assume for the moment that you are close enough to make a positive identification and with that, you can look up the exact length of the ship. Later, I suspect we'll be able to just put in approximations for different classes of ships and the calculation will still be valid to with a few degrees AoB. But for now, let's just assume we have perfect information about ship length. Given the following... So the ship is out there, I don't know how far away it is, but that's not important for determining AoB. All I do is get a measurement of the length of the ship as it appears in my scope. In this case I determine the length that I see is 34m. I know the length of the ship (side c) is 95m. I just observed side a as 34m. Given these two measurements, I should be able to solve for angle bc which is equivalent to AoB. The formula in Excel would look like this: Note: Excel trig functions return radians hence the 180/Pi conversion to degrees =ASIN(34/95) * 180/3.14159265358979 =20.97° So, I'm thinking that all I need is a gadget in MoBo that helps me measure the observed length of the ship, and if I know from the ship recog manual what the length is, I should be able to input those two values and get the AoB. :hmm: Do you think this would work? ...not quite sure yet how to deal with the scaling issue of an observation; even at 1x mag. If a vertical stadimeter works wouldn't a horizontal one work as well? If anyone knows for sure that it's a lost cause trying to calculate "side a" just let me know. __________________ Last edited by XLjedi; 01-09-09 at 03:04 PM.

01-09-09, 03:16 PM	#2
XLjedi Ace of the Deep Join Date: Jun 2005 Location: Palm Beach, Florida Posts: 1,243 Downloads: 53 Uploads: 8	Hmmm... the more I think about it, the more I think it will be impossible to determine a true length for "side a" without knowing the distance. Ah well, back to the drawing board. __________________

01-10-09, 06:09 AM	#3
Hitman Pacific Aces Dev Team Join Date: Sep 2002 Location: Spain Posts: 6,109 Downloads: 109 Uploads: 2	Yes, I was about to point that out: You need the distance to the ship in order to be able of determining the AOB. Or at least, you need to calculate the "Aspect Ratio" as suggested in my tutorial for manual shooting with SH4: http://files.filefront.com/Simplifie.../fileinfo.html __________________ One day I will return to sea ...

01-21-09, 04:39 PM	#9
Hitman Pacific Aces Dev Team Join Date: Sep 2002 Location: Spain Posts: 6,109 Downloads: 109 Uploads: 2	As much as MoBo was developed initially for SH3/4, IMHO it should shine even more when used in modern sub warfare games like Sub Command or Dangerous Waters There you do bearings-only TMA with different legs and need more calculations and geometry than with WW2 tactics. __________________ One day I will return to sea ...

01-21-09, 02:58 AM	#4
Robert Fulton Mate Join Date: Oct 2008 Location: USA Posts: 59 Downloads: 2 Uploads: 0	Maybe there is another method that could work in some if not all cases. The horizontal measurements on the target vary with both distance and AOB. But vertical measurements vary only with distance. Can we not then use the ratio of the vertical measurements to the horizontal measurements compared to the known ratios from the ID manual to help us compute AOB? (It is pushing 3:00am, so working on the actual formulas right now is not an option.)

01-21-09, 11:24 AM	#6
Robert Fulton Mate Join Date: Oct 2008 Location: USA Posts: 59 Downloads: 2 Uploads: 0	Hmmm..... It seems it was later than I thought. Not only did I maybe misunderstand your original question, but I as I read Hitman's post, his reference to "aspect ratio" seems to cover the ground I did anyhow. (I have not downloaded his file, as I have yet to crack open SH4.) Aaron, as I have stated previously, MoBo is awesome and I am appreciative of the effort and skill applied to create it. Also, congrats on your promotion to Ace of the Deep.